Frantic parents fear for kids after radioactive contamination found at Ohio middle school

[Igel]

15. It's a naturally occurring isotope.

With a long half life. This isn't a reactor that we're talking about, or a nuclear waste processing plant. It's a gaseous diffusion enrichment plant that's been decommissioned.

The isotope decays by emitting an alpha particle. Unless the radioactive stuff is internal, alpha particles aren't just a huge deal; if they're inside your body, then it's a huge deal. That dead skin you carry with you is protection against all but the highest energy alpha particles.

That it's airborne is a problem; that they haven't determined the level of radiation says it's probably old. Since the two isotopes have half lives of a million years or more, they're not all that hot.